Field Application of Solid Oxygen Source for Bioremediation

A contaminated field site was created in the subsurface soil by introducing propylene glycol (PPG). The soil at the site is an overconsolidated silty clay of very low permeability (hydraulic conductivity about 10-7 cm/sec). After a period of acclimation, the soil was hydraulically fractured using a mixture of sand, encapsulated sodium percarbonate, and IBDU slow-release fertilizer. In the vicinity of the fractures, microbial metabolic rate increases were observed as well as increases in the microbial population of 10 to 100 fold. The PPG was observed at lower concentrations near the fractures compared to above the fractures by the end of the incubation. After four months in the soil, the rate of oxygen release from the fracture layer was still 2.6% of its initial rate of oxygen release.